The present invention relates to lifting devices. More particularly, the present invention relates to an apparatus suspended from an overhead support for lifting an object, especially an elongated object such as a watercraft.
Many types of objects are carried about on trailers or on the tops of motor vehicles, including watercraft. As an example, the owner of a boat may reside some distance from a water body, and not have access to watercraft storage at the body of water. The boat owner may store his boat at his home in a garage, and carry the boat on his automobile roof or on a trailer from the garage to the body of water for use. For storage, the boat must be removed from the automobile or trailer and transferred to a storage position. Many types of boats are sufficiently heavy as to make transfer from the automobile or trailer a difficult or even impossible task for a single individual.
Lifting devices for such purposes are known in the prior art. These devices as presently known, however, leave many problems unresolved.
As an example, some prior art lifting devices do not utilize a single haul line. Because of the size and shape of generally elongate objects such as watercraft, multiple support points on the object may be required for raising and lowering. For example, a watercraft may require a support to be placed under it near its stern and a second under it near its bow. These supports must generally be raised or lowered substantially simultaneously. Operation of such devices thus requires one person per support, thereby making operation by a single individual impractical or impossible. Solutions to multiple lifting points requiring multiple individuals have been proposed. These solutions, however, have heretofore been overly complicated and costly.
Other lifting devices of the prior art are not suitable to lift objects of substantial weight. These devices generally comprise ropes attached to the object and directed through pulleys to a lifting location. Minimal mechanical advantage is provided, however, so that objects of substantial weight, such as a jet ski or small motor boat cannot be lifted by an individual. Lifting devices have been proposed that provide mechanical advantages through cranks, winches, and the like. These devices, however, tend to be overly complicated and expensive, making them impractical and disadvantageous.
An unresolved need therefore exits for a lifting device suitable for use by a single individual and capable of lifting objects of substantial weight.
It is an object of the invention to provide a lifting device for lifting an object.
It is a further object of the invention to provide a lifting device having a mechanical advantage and suitable for lifting a water craft through manipulation of a single line.
The present invention comprises a lifting device for raising and lowering an elongate object into a storage position, the lifting device comprising at least a first and a second pair of pulleys, the first and second pairs of pulleys being spaced from one another along a longitudinal axis, each individual pulley of said first and second pair of pulleys spaced laterally from the longitudinal axis, with the first and second pair of pulleys connected to an upright support. Individual lines pass over each individual of the pairs of pulleys, each of the individual lines have means for attachment to the elongate object, and each of the individual lines further comprise second ends.
The lifting device further comprises a multiple purchase block and tackle system spaced from one of the pairs of pulleys along the longitudinal axis. The multiple purchase block and tackle system comprises a first and a second end, and an adjustable hauling line reeved between the ends for moving the ends towards one another with multiple purchase. The block and tackle system first end is connected to each of the second ends of the individual lines, and the block and tackle system second end is attached to an upright support such as a garage wall. Hauling on the hauling line thereby urges block and tackle system first end towards the second end along the longitudinal axis, further causing simultaneous movement of the individual lines for raising and lowering the elongate object.
The present invention thereby presents an apparatus that offers substantial mechanical advantage through the block and tackle system for raising and lowering of objects. Further, because the individual lines are connected to one end of the block and tackle system, the object may be raised or lowered through the manipulation of the haul line only.
Preferably, the lifting device further comprises gathering means for gathering and leading the individual lines substantially along the longitudinal axis. Most preferably, the gathering means comprise at least a pair of rotating pulleys. By gathering the individual lines substantially along the longitudinal axis, they may move a substantially equal distance along the axis when the hauling line is hauled to move the ends of the multiple purchase system towards or away from one another. This results in the object being lifted a substantially equal amount by each of the individual lines, for a smooth and level raising.
The lifting device of the present invention thus comprises a relatively simple to construct, low cost, and easy to install device. Through the multiple purchase block and tackle system the device provides means for lifting objects of substantial weight and size by a single individual through manipulation of a single hauling line. Further, with the preferred gathering means, each of the individual lines may be drawn an equal amount by the block and tackle system so that the object is uniformly raised and lowered by the multiple lines through manipulation of the single haul line. The present invention thus solves several heretofore unresolved problems in an efficient and elegant manner.